Unfortunately it is common. However, there is also a TSB (Service Bulletin Number: 04-13-4 ) regarding a particular issue related to the TOB but it sounds like you're looking at a "normal" service item. How many miles on your car?
Sounds like the usual bothersome bird in your tranny is going to cost a lot. Mine has gone out a few times on different cars. Ford tries their hardest to not cover it, especially with 20,000miles on the odometer.
On a side note, if you're going to have it replaced, throw in a clutch at the same time. I would use either a Timkin or Valeo TOB... Just my 2cents.
Here are a few possible temp-fixes.
1. White lithium Grease
2. New Quadrant and firewall adjuster (helped a tad)
3. Snap clutch cable like I did (no noise, but no go)
I have this problem, but it doesn't happen all the time. It is embarrassing at times. My snake has 9,000 miles on it. I am going to get it replaced before I hit the majic 12,000. No questions asked.